Targeted therapy for renal cell carcinoma: The next lap

Expression of TXNIP is associated with angiogenesis and postoperative relapse of conventional renal cell carcinoma

One of the common mediator of tumour progression is the oxidative stress induced by inflammatory tumour microenvironment (TME). Activated fibroblasts, local and immune cells produce reactive oxygen species (ROS) supporting tumour cell proliferation and pave the way for metastatic tumour growth. TXNIP regulates ROS generation by inhibiting the antioxidative function of thioredoxin (TXN). The shift of TXNIP/TXN balance towards overexpression of TXNIP is associated with proliferation of endothelial cells during tumor angiogenesis. The oxidative stress activates the hypoxia inducible factor-1 (HIF-1), which plays an important role in the biology of conventional RCC (cRCC). Under oxydative stress TXNIP interacts with NLRP3 inflammasome leading to maturation and secretion of inflammatory cytokine IL1β. To establish the role of TXNIP and downstream genes HIF1α and IL1β in the biology of cRCC, we have applied immunohistochemistry to multi-tissue arrays containing tumours of 691 patients without detectable metastases at the time of operation. We found that cRCC displaying a fine organised capillary network with nuclear translocation of TXNIP and expressing IL1β have a good prognosis. In contrary, we showed a significant correlation between cytoplasmic TXNIP expression, inefficient vascularisation by unorganized and tortuous vessels causing tumour cell necrosis and postoperative tumour relapse of cRCC.

Development of Taccalonolide AJ-Hydroxypropyl-β-Cyclodextrin Inclusion Complexes for Treatment of Clear Cell Renal-Cell Carcinoma

BACKGROUND

Microtubule-targeted drugs are the most effective drugs for adult patients with certain solid tumors. Taccalonolide AJ (AJ) can stabilize tubulin polymerization by covalently binding to β-tubulin, which enables it to play a role in the treatment of tumors. However, its clinical applications are largely limited by low water solubility, chemical instability in water, and a narrow therapeutic window. Clear-cell renal-cell carcinoma (cc RCC) accounts for approximately 70% of RCC cases and is prone to resistance to particularly targeted therapy drugs.

METHODS

we prepared a water-soluble cyclodextrin-based carrier to serve as an effective treatment for cc RCC.

RESULTS

Compared with AJ, taccalonolide AJ-hydroxypropyl-β-cyclodextrin (AJ-HP-β-CD) exhibited superior selectivity and activity toward the cc RCC cell line 786-O vs. normal kidney cells by inducing apoptosis and cell cycle arrest and inhibiting migration and invasion of tumor cells in vitro. According to acute toxicity testing, the maximum tolerated dose (MTD) of AJ-HP-β-CD was 10.71 mg/kg, which was 20 times greater than that of AJ. Assessment of weight changes showed that mouse body weight recovered over 7-8 days, and the toxicity could be greatly reduced by adjusting the injections from once every three days to once per week. In addition, we inoculated 786-O cells to generate xenografted mice to evaluate the anti-tumor activity of AJ-HP-β-CD in vivo and found that AJ-HP-β-CD had a better tumor inhibitory effect than that of docetaxel and sunitinib in terms of tumor growth and endpoint tumor weight. These results indicated that cyclodextrin inclusion greatly increased the anti-tumor therapeutic window of AJ.

CONCLUSIONS

the AJ-HP-β-CD complex developed in this study may prove to be a novel tubulin stabilizer for the treatment of cc RCC. In addition, this drug delivery system may broaden the horizon in the translational study of other chemotherapeutic drugs.

RCC Immune Microenvironment Subsequent to Targeted Therapy: A Friend or a Foe?

Renal cell carcinoma (RCC) is composed of different subtypes with distinct molecular and histological tumor heterogeneity. Although the advent of various targeted therapies has improved the survival of patients with advanced RCC over the past 15 years (since 2006), few cases experienced complete response due to drug resistance. Recent studies have demonstrated that the outcomes following targeted therapies are potentially associated with intricate cross-links between immune responses and suppressors in the tumor microenvironment (TME). In addition, progress on drug research and development enhances our awareness and understanding about immunotherapy and combined treatment. In this review article, we intend to make a comprehensive summary about TME and its alterations following targeted therapies, provide valid evidence in this aspect, and discuss optimal matches between targeted therapy and immunotherapy.

Biological Evaluation of Oxindole Derivative as a Novel Anticancer Agent against Human Kidney Carcinoma Cells

Renal cell carcinoma has emerged as one of the leading causes of cancer-related deaths in the USA. Here, we examined the anticancer profile of oxindole derivatives (SH-859) in human renal cancer cells. Targeting 786-O cells by SH-859 inhibited cell growth and affected the protein kinase B/mechanistic target of rapamycin 1 pathway, which in turn downregulated the expression of glycolytic enzymes, including lactate dehydrogenase A and glucose transporter-1, as well as other signaling proteins. Treatment with SH-859 altered glycolysis, mitochondrial function, and levels of adenosine triphosphate and cellular metabolites. Flow cytometry revealed the induction of apoptosis and G0/G1 cell cycle arrest in renal cancer cells following SH-859 treatment. Induction of autophagy was also confirmed after SH-859 treatment by acridine orange and monodansylcadaverine staining, immunocytochemistry, and Western blot analyses. Finally, SH-859 also inhibited the tumor development in a xenograft model. Thus, SH-859 can serve as a potential molecule for the treatment of human renal carcinoma.

Expression of RARRES1 and AGBL2 and progression of conventional renal cell carcinoma

BACKGROUND

Approximately 15% of clinically localised conventional renal cell carcinoma (RCC) will develop metastasis within 5 years of follow-up. The aim of this study was to identify biomarkers predicting the postoperative tumour relapse.

METHODS

Tissue microarrays of conventional RCC from a cohort of 691 patients without metastasis at the time of operation were analysed by immunohistochemistry for the expression of carboxypeptase inhibitor RARRES1 and its substrate carboxypeptidase AGBL2. Univariate and multivariate Cox regression models were addressed to postoperative tumour relapse and the metastasis-free survival time was estimated by Kaplan-Meier analysis.

RESULTS

In multivariate analysis, the lack of staining or cytoplasmic staining of RARRES1 was a significant risk factor indicating five times higher risk of cancer relapse. Combining its co-expression with AGBL2, we found that RARRES1 cytoplasmic/negative and AGBL2-positive/negative staining is a significant risk factor for tumour progression indicating 11-15 times higher risk of cancer relapse, whereas the membranous RARRES1 expression, especially its co-expression with AGBL2, associated with excellent disease outcome.

CONCLUSIONS

RARRES1 and AGBL2 expression defines groups of patients at low and high risk of tumour progression and may direct an active surveillance to detect metastasis as early as possible and to apply adjuvant therapy.

Long non-coding RNA TCL6 enhances preferential toxicity of paclitaxel to renal cell carcinoma cells

Background: Recent findings have shown long non-coding RNAs (lncRNAs) are dysregulated in a variety of cancer cells. In this report, we investigate the effect of T-cell leukemia lymphoma 6 (TCL6) on paclitaxel (PTX)-induced apoptosis in Renal cell carcinoma (RCC) cells. Methods: Expression levels of TCL6 in RCC tissues were analyzed via The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets. Fluorescence in situ hybridization (FISH) was performed to detect the expression of TCL6 in RCC tissues and cells. Two pairs of cell lines were used: TCL6-silenced 786-O cell line and scrambled 786-O cell line, TCL6-overexpressed Caki-1 cell line and Caki-1 scrambled cell line. Cell viability was detected using the MTT assay. Apoptosis was examined by flow cemetery. Dual reporter gene assay was performed to confirm the direct downstream target miRNA of TCL6. Results: Based on RNA sequencing expression data of RCC tissues from TCGA and GEO datasets, the expression deficiency of TCL6 was observed in RCC tissues. Low level of TCL6 was associated with worse overall and disease-free survival of RCC patients. The FISH showed similar results with low expression of TCL6 in RCC tissues and cells. After PTX treatment, a time-dependent decrease in cell viability was observed in TCL6-overexpressed RCC cells and an increase in cell viability was observed in TCL6-silenced cells compared to control cells. Apoptosis induced by PTX was significantly increased in TCL6-overexpressed cells. Inhibition of TCL6 showed a significant decrease in apoptosis. Furthermore, luciferase reporter assay revealed that TCL6 is a direct target gene of miR-221. Conclusions: TCL6 effectively sensitizes RCC to PTX mainly through downregulation of miR-221. Our results suggest that PTX combined with TCL6 might be a potentially more effective chemotherapeutic approach for renal cancer.

Knockdown of Pyruvate Kinase M2 Inhibits Cell Proliferation, Metabolism, and Migration in Renal Cell Carcinoma

Emerging evidence indicates that the activity of pyruvate kinase M2 (PKM2) isoform is crucial for the survival of tumor cells. However, the molecular mechanism underlying the function of PKM2 in renal cancer is undetermined. Here, we reveal the overexpression of PKM2 in the proximal tubule of renal tumor tissues from 70 cases of patients with renal carcinoma. The functional role of PKM2 in human renal cancer cells following small-interfering RNA-mediated PKM2 knockdown, which retarded 786-O cell growth was examined. Targeting PKM2 affected the protein kinase B (AKT)/mechanistic target of the rapamycin 1 (mTOR) pathway, and downregulated the expression of glycolytic enzymes, including lactate dehydrogenase A and glucose transporter-1, and other downstream signaling key proteins. PKM2 knockdown changed glycolytic metabolism, mitochondrial function, adenosine triphosphate (ATP) level, and intracellular metabolite formation and significantly reduced 786-O cell migration and invasion. Acridine orange and monodansylcadaverine staining, immunocytochemistry, and immunoblotting analyses revealed the induction of autophagy in renal cancer cells following PKM2 knockdown. This is the first study to indicate PKM2/AKT/mTOR as an important regulatory axis mediating the changes in the metabolism of renal cancer cells.

Limitations to the Therapeutic Potential of Tyrosine Kinase Inhibitors and Alternative Therapies for Kidney Cancer

Background: Renal cell carcinomas (RCCs) are the most common primary renal tumor. RCCs have a high rate of metastasis and have the highest mortality rate of all genitourinary cancers. They are often diagnosed late when metastases have developed, and these metastases are difficult to treat successfully. Since 2006, the standard first-line treatment for patients with metastatic RCC has been multitargeted tyrosine kinase inhibitors (TKIs) that include mammalian target of rapamycin (mTOR) inhibitors. RCCs are highly vascularized tumors, and their angiogenesis is controlled by tyrosine kinases that play a vital role in growth factor signaling to stimulate this process. TKI therapy was introduced for direct targeting of angiogenesis in RCC. TKIs have been moderately successful in the treatment of metastatic RCC and initially increased cancer-specific survival times. However, RCC rapidly becomes resistant to TKIs, and no current drug has produced a cure for advanced RCC. Methods: We provide an overview of RCC, explain some reasons for therapy resistance in RCC, and describe some therapies that may overcome resistance to TKIs. The key pathways that determine therapy resistance are illustrated. Results: Factors involved in the development and progression of RCC include genetic mutations, activation of hypoxia-inducible factor and related proteins, cellular metabolism, the tumor microenvironment, and growth factors and their receptors. Resistance to the therapeutic potential of TKIs can be acquired or intrinsic. Alternative therapies include other small molecule drugs and immunotherapy based on immune checkpoint blockade. Conclusion: The treatment of RCC is undergoing a paradigm shift from sole use of small molecule antiangiogenesis TKIs as first-line therapy to include newly approved agents for second-line and third-line therapy that now involve the mTOR pathway and immune checkpoint blockade drugs for patients with advanced RCC.

Patient-derived xenograft models to optimize kidney cancer therapies

Renal cell carcinoma (RCC) is the most common solid neoplasm of the adult kidney and has a high potential for developing metastatic spread. Approximately 25-30% of RCC patients have metastatic disease at presentation, and 30-40% of patients develop metastases after the initial diagnosis. Advanced renal cancer is a deadly and difficult-to-treat cancer. The 5-year survival rate of patients with metastatic disease is less than 10%, partly because RCC metastases become resistant to current therapies. Pre-clinical models may help to identify the optimum therapeutic options for individual patients. Here we reviewed various mouse xenograft methods for RCC treatment screening especially patient-derived orthotopic xenograft models. Advantages and disadvantaged of some of the models are also discussed.

Dauricine inhibits viability and induces cell cycle arrest and apoptosis via inhibiting the PI3K/Akt signaling pathway in renal cell carcinoma cells

Renal cell carcinoma (RCC), which is derived from the proximal tubules of nephrons, is one of the most common solid cancers. Due to its inherent insensitivity to radiotherapy and chemotherapy, surgery remains the only curative strategy for RCC. Therefore, a novel strategy for treating RCC is urgently needed. This study aims to investigate the effects of dauricine, a bisbenzylisoquinoline alkaloid, in RCC cells and the underlying mechanisms of its action. The effects of dauricine on viability, cell cycle distribution and apoptosis in RCC cells were determined in vitro by MTT assay, flow cytometry and nucleosome ELISA assay, respectively. Mechanism studies were performed by analyzing related proteins using western blotting assays. We show that dauricine effectively inhibits the viability of four RCC cell lines (786‑O, Caki‑1, A‑498 and ACHN). In addition, dauricine induces cell cycle arrest at the G0/G1 phase in RCC cells. Dauricine also induces apoptosis via the intrinsic pathway, since caspase‑9 and caspase‑3 but not caspase‑8 activation was detected after the treatment. Moreover, dauricine was able to inhibit the PI3K/Akt signaling pathway. Our findings suggest inhibitory effects of dauricine in renal cancer cells and provide a better understanding of its underlying mechanism. Our findings suggest that dauricine could be a potential therapeutic agent for treating RCC.

Pyrvinium Sensitizes Clear Cell Renal Cell Carcinoma Response to Chemotherapy Via Casein Kinase 1α-Dependent Inhibition of Wnt/β-Catenin

BACKGROUND

Aberrant Wnt/β-catenin activation has been shown to play essential roles in cancer, including renal cell carcinoma (RCC). In this work, we demonstrate that Wnt/β-catenin inhibition by a Food and Drug Administration-approved drug, pyrvinium, effectively targets clear cell RCC and enhances chemotherapy agent's efficacy.

MATERIALS AND METHODS

We performed in vitro cell culture assays and in vivo xenograft tumor model to evaluate the effects of pyrvinium alone and its combination with paclitaxel, and analyzed the underlying mechanism(s) of pyrvinium's action in RCC.

RESULTS

We show that pyrvinium inhibits growth and induces apoptosis via caspase pathway in a panel of RCC cell lines. It decreases β-catenin activity and its downstream Wnt-targeted genes transcription via axin-mediated β-catenin protein reduction. Overexpression of β-catenin completely reverses the effects of pyrvinium, demonstrating that β-catenin inhibition is required for pyrvinium's action in clear cell RCC. Furthermore, we found that pyrvinium failed to decrease β-catenin protein level and activity in casein kinase 1α (CK1α)-depleted clear cell RCC cells, demonstrating that pyrvinium inhibits β-catenin in a CK1α-dependent manner. Notably, decreased tumor growth and β-catenin levels were observed in clear cell RCC xenograft mouse model treated with pyrvinium. Combination of pyrvinium and paclitaxel resulted in greater efficacy in in vitro and in vivo.

CONCLUSIONS

Our findings suggest that pyrvinium is a useful addition to the treatment armamentarium for clear cell RCC. Our work also demonstrate that targeting Wnt/β-catenin is a potential therapeutic strategy in clear cell RCC.

Antibiotic ivermectin preferentially targets renal cancer through inducing mitochondrial dysfunction and oxidative damage

Renal cell carcinoma (RCC) is the most aggressive type of genitourinary cancer and highly resistant to current available therapies. In this work, we investigated the effects and mechanism of anti-parasitic agent ivermectin in RCC. We show that ivermectin significantly inhibits proliferation and induces apoptosis in multiple RCC cell lines that represent different histological subtypes and various mutation status. Importantly, ivermectin is significantly less or ineffective in normal kidney cells compared with RCC cells, demonstrating the preferential toxicity of ivermectin to RCC. Ivermectin also significantly inhibits RCC tumor growth in vivo. Mechanistically, ivermectin induces mitochondrial dysfunction via decreasing mitochondrial membrane potential, mitochondrial respiration and ATP production. As a consequence of mitochondrial dysfunction, oxidative stress and damage is detected in ivermectin treated RCC cells and xenograft mouse model. The rescue of ivermectin's effect by acetyl-l-Carnitine (ALCAR, a mitochondrial fuel) or antioxidant N-acetyl-l-cysteine (NAC) confirms mitochondria as the target of ivermectin in RCC cells. Compared to normal kidney cells, RCC cells have higher mitochondrial mass and respiration, and ATP production, which might explain the preferential toxicity of ivermectin to RCC. Our work suggest that ivermectin is a promising candidate for RCC treatment and targeting mitochondrial metabolism is an alternative therapeutic strategy for RCC.

An integrated analysis of cancer genes in clear cell renal cell carcinoma

AIM

This study was performed to detect driver genes and implement integrated analyses on these drivers in clear cell renal cell carcinoma (ccRCC).

METHODS

Driver genes and pathways were predicted by OncodriveFM and Dendrix using 39,636 somatic mutations from The Cancer Genome Atlas, followed by DNA methylation, copy number variation, differential expression and survival analyses.

RESULTS

Overall, 342 driver genes and 106 pathways were determined by OncodriveFM, two driver genes by Dendrix. 28 driver genes were found hypomethylated, overexpressed and associated to a poor prognosis. By contrast, 17 driver genes showed decreased expression, hypermethylation and indicated a better outcome in ccRCC.

CONCLUSION

The set of new cancer genes and pathways opens the avenue for developing potential therapeutic targets and prognostic biomarkers in ccRCC.

The Role of Hypoxia and Cancer Stem Cells in Renal Cell Carcinoma Pathogenesis

The cancer stem cell (CSC) model has recently been approached also in renal cell carcinoma (RCC). A few populations of putative renal tumor-initiating cells (TICs) were identified, but they are indifferently understood; however, the first and most thoroughly investigated are CD105-positive CSCs. The article presents a detailed comparison of all renal CSC-like populations identified by now as well as their presumable origin. Hypoxic activation of hypoxia-inducible factors (HIFs) contributes to tumor aggressiveness by multiple molecular pathways, including the governance of immature stem cell-like phenotype and related epithelial-to-mesenchymal transition (EMT)/de-differentiation, and, as a result, poor prognosis. Due to intrinsic von Hippel-Lindau protein (pVHL) loss of function, clear-cell RCC (ccRCC) develops unique pathological intra-cellular pseudo-hypoxic phenotype with a constant HIF activation, regardless of oxygen level. Despite satisfactory evidence concerning pseudo-hypoxia importance in RCC biology, its influence on putative renal CSC-like largely remains unknown. Thus, the article discusses a current knowledge of HIF-1α/2α signaling pathways in the promotion of undifferentiated tumor phenotype in general, including some experimental findings specific for pseudo-hypoxic ccRCC, mostly dependent from HIF-2α oncogenic functions. Existing gaps in understanding both putative renal CSCs and their potential connection with hypoxia need to be filled in order to propose breakthrough strategies for RCC treatment.

Niclosamide suppresses renal cell carcinoma by inhibiting Wnt/β-catenin and inducing mitochondrial dysfunctions

PURPOSE

To investigate the effects of anthelminthic drug niclosamide in renal cell carcinoma (RCC) and the underlying mechanisms of its action.

METHODS

The effects of niclosamide on the proliferation and apoptosis of RCC cells were examined in vitro and in vivo by using MTS, colony formation assay, flow cytometry and xenograft cancer mouse model. Mechanism studies were performed by analyzing Wnt/β-catenin signaling and mitochondrial functions in a panel of RCC cell lines.

RESULTS

We show that niclosamide effectively targets two RCC cell lines through inhibiting proliferation and anchorage-independent colony formation, and inducing apoptosis. It also enhances the inhibitory effects of chemotherapeutic drug cisplatin in two independent in vivo RCC xenograft mouse models. Mechanistically, niclosamide decreases β-catenin levels and therefore suppresses Wnt/β-catenin activities. Overexpression of β-catenin partially reverses the inhibitory effects of niclosamide in RCC cells, demonstrating that besides β-catenin, other mechanisms are involved in niclosamide's anti-cancer activity. Indeed, we further show that niclosamide induces mitochondrial dysfunctions as shown by the decreased level of mitochondrial membrane potential and respiration, resulting in decreased ATP levels and increased reactive oxygen species (ROS) levels.

CONCLUSIONS

Our findings support the inhibitory effects of niclosamide in cancer and provide better understanding on its underlying mechanism. Our data suggests that niclosamide is a useful addition to the treatment armamentarium for RCC.

Metastatic clear cell renal carcinoma - an unusual response to Temsirolimus in second line therapy

Renal cell carcinoma (RCC) represents 3% of all cancers, with the highest incidence occurring in the most developed countries and representing the seventh most common cancer in men and the ninth most common cancer in women. The understanding of the tumor molecular biology and the discovery of new drugs that target molecular pathways have increased the arsenal against advanced renal cell carcinoma and improved the outcomes in the patients suffering from these affections. Studying the molecular signaling that controls the tumor growth and the progression has led to the development of molecular therapies targeting the vascular endothelial growth factor (VEGF) and mammalian target of rapamycin (mTOR) pathways, resulting in a significant improvement in the overall survival and quality of life. Sunitinib represents an inhibitor of VEGFR 1-3, c-kit, FLT-3 and PDGFR. We present the case of a patient with metastatic clear cell RCC with a treatment effect following sequential VEGF and mTOR inhibitor treatment. Under sunitinib treatment, the patient had a progression free survival (PFS) of approximately 9 months, similar to the PFS observed in clinical trials. Sunitinib was well tolerated by this patient. Temsirolimus, an mTOR inhibitor, is currently only approved for the first-line treatment of mRCC patients with poor prognosis. This study analyzes a treatment effect of second line temsirolimus in a patient with metastatic renal cell carcinoma (mRCC).

Targeting MET and AXL overcomes resistance to sunitinib therapy in renal cell carcinoma

Antiangiogenic therapy resistance occurs frequently in patients with metastatic renal cell carcinoma (RCC). The purpose of this study was to understand the mechanism of resistance to sunitinib, an antiangiogenic small molecule, and to exploit this mechanism therapeutically. We hypothesized that sunitinib-induced upregulation of the prometastatic MET and AXL receptors is associated with resistance to sunitinib and with more aggressive tumor behavior. In the present study, tissue microarrays containing sunitinib-treated and untreated RCC tissues were stained with MET and AXL antibodies. The low malignant RCC cell line 786-O was chronically treated with sunitinib and assayed for AXL, MET, epithelial-mesenchymal transition (EMT) protein expression and activation. Co-culture experiments were used to examine the effect of sunitinib pretreatment on endothelial cell growth. The effects of AXL and MET were evaluated in various cell-based models by short hairpin RNA or inhibition by cabozantinib, the multi-tyrosine kinases inhibitor that targets vascular endothelial growth factor receptor, MET and AXL. Xenograft mouse models tested the ability of cabozantinib to rescue sunitinib resistance. We demonstrated that increased AXL and MET expression was associated with inferior clinical outcome in patients. Chronic sunitinib treatment of RCC cell lines activated both AXL and MET, induced EMT-associated gene expression changes, including upregulation of Snail and β-catenin, and increased cell migration and invasion. Pretreatment with sunitinib enhanced angiogenesis in 786-0/human umbilical vein endothelial cell co-culture models. The suppression of AXL or MET expression and the inhibition of AXL and MET activation using cabozantinib both impaired chronic sunitinib treatment-induced prometastatic behavior in cell culture and rescued acquired resistance to sunitinib in xenograft models. In summary, chronic sunitinib treatment induces the activation of AXL and MET signaling and promotes prometastatic behavior and angiogenesis. The inhibition of AXL and MET activity may overcome resistance induced by prolonged sunitinib therapy in metastatic RCC.

Axl receptor tyrosine kinase is a potential therapeutic target in renal cell carcinoma

Background:

Axl plays multiple roles in tumourigenesis in several cancers. Here we evaluated the expression and biological function of Axl in renal cell carcinoma (RCC).

Methods:

Axl expression was analysed in a tissue microarray of 174 RCC samples by immunostaining and a panel of 11 normal tumour pairs of human RCC tissues by western blot, as well as in RCC cell lines by both western blot and quantitative PCR. The effects of Axl knockdown in RCC cells on cell growth and signalling were investigated. The efficacy of a humanised Axl targeting monoclonal antibody hMAb173 was tested in histoculture and tumour xenograft.

Results:

We have determined by immunohistochemistry (IHC) that Axl is expressed in 59% of RCC array samples with moderate to high in 20% but not expressed in normal kidney tissue. Western blot analysis of 11 pairs of tumour and adjacent normal tissue show high Axl expression in 73% of the tumours but not normal tissue. Axl is also expressed in RCC cell lines in which Axl knockdown reduces cell viability and PI3K/Akt signalling. The Axl antibody hMAb173 significantly induced RCC cell apoptosis in histoculture and inhibited the growth of RCC tumour in vivo by 78%. The hMAb173-treated tumours also had significantly reduced Axl protein levels, inhibited PI3K signalling, decreased proliferation, and induced apoptosis.

Conclusions:

Axl is highly expressed in RCC and critical for RCC cell survival. Targeting Axl is a potential approach for RCC treatment.

Comparison of sorafenib-loaded poly (lactic/glycolic) acid and DPPC liposome nanoparticles in the in vitro treatment of renal cell carcinoma

The objective of this study is to develop and compare several Sorafenib-loaded biocompatible nanoparticle models in order to optimize drug delivery and tumor cellular kill thereby improving the quality of Sorafenib-regimented chemotherapy. Sorafenib-loaded poly (lactic-co-glycolic) acid (PLGA), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes, and hydrophobically modified chitosan (HMC)-coated DPPC liposomes were evaluated for several characteristics including zeta potential, drug loading, and release profile. Cytotoxicity and uptake trials were also studied using cell line RCC 786-0, a human metastatic clear cell histology renal cell carcinoma cell line. Sorafenib-loaded PLGA particles and HMC-coated DPPC liposomes exhibited significantly improved cell kill compared to Sorafenib alone at lower concentrations, namely 10-15 and 5-15 μM from 24 to 96 h, respectively. At maximum dosage and time (15 μM and 96 h), Sorafenib-loaded PLGA and HMC-coated liposomes killed 88.3 ± 1.8% and 98 ± 1.1% of all tumor cells, significant values compared with Sorafenib 81.8 ± 1.7% (p < 0.01). Likewise, HMC coating substantially improved cell kill for liposome model for all concentrations (5-15 μM) and at time points (24-96 h) (p < 0.01). PLGA and HMC-coated liposomes are promising platforms for drug delivery of Sorafenib. Because of different particle characteristics of PLGA and liposomes, each model can be further developed for unique clinical modalities.

Assessing the impact of evolving evidence in renal cell carcinoma treatment: an update of the Renal Cell Carcinoma Appropriateness-based Treatment Toolkit (ReCATT)

The appropriateness of the numerous therapeutic options available for patients with advanced or metastatic renal cell carcinoma (RCC) was evaluated in 2011, using the RAND/University of California, Los Angeles (UCLA) appropriateness methodology to match treatment suitability to a range of patient scenarios. However, the RCC therapeutic area evolves rapidly and a body of new clinical data has accrued in the intervening years; as a result the exercise was repeated in 2013 using the same methodology, expert panel and patient scenarios. The aim of the updated assessment was to update the guidance to clinicians and use it to develop an interactive web-based application, the Renal Cell Carcinoma Appropriateness-based Treatment Toolkit (ReCATT). This round of assessment achieved greater concordance concerning the appropriateness of treatments/interventions for the clinical scenarios tested; this higher level of agreement is likely to reflect the body of scientific evidence accrued since the previous assessment exercise. Many of the areas of disagreement in 2011 related to the suitability of pazopanib or sunitinib treatment; in the 2013 assessment both agents were considered appropriate treatment options for many of the clinical scenarios assessed. Uncertain scenarios often are related to the optimal management of metastatic RCC with clear cell histology. The use of the RAND/UCLA RCC assessment findings to develop the ReCATT support tool will help to disseminate expert opinion concerning best treatment practice and guide the clinical management of RCC patients treated in the community setting.